Measuring and control apparatus



Feb. 17, 1942.

T. R. HARRISQN MEASURING AND CON'IiROL APPARATUS Original Filed Sept.

a R \M w 1? w 2. F w V I h l .P .2 kl m m w 1 r I N x wi lfl lhv I N...H. m 1 m K & m. N H S. fw s I". m 7. A E v m E .H I w W m 1] I z mv L m0m6 Q w F, I- n E .u 7.0 .m q 8 L ow a a mo 1 N m 0 w 0 mm mm m0 h I 0 ll4w .3 0 mfl 0 46 0 THOMAS R. HARRISON AT'roNEY Patented Feb. 17, 1942MEASURING AND CONTROL APPARATUS Thomas R... Harrison, Wyncote, Pa.,assignor to The Brown Instrument Company, Philadelphia,

Pa., a corporation of Pennsylvania Original application September 11,1935, serial-no.

40,103. Divided and this application January 21, 1939, Serial No.253,135

(o1. zoo-14) 3 Claims.

The general object of the present invention is to provide an improvedcontrol mechanism including novel means for effecting control actionswhich are a joint function of two quantities varying independently ofone another. specific object of the invention is to provide an improvedcontrol system for a liquid heating furnace, comprising novel andeffective meansv A more a part of this specification. For a betterunderstanding of the invention, however, its advantages, and specificobjects attained with its use, reference should be had-to theaccompanying drawing and descriptive matter in which I have illustratedand described a preferred embodiment of the invention.

The one figure of the drawing is a diagrammatic representation of an oilstill and associated fuel control means.

In the drawing, I have illustrated the use of the present invention inregulating the supply of fuel to an oil still or heater S, in which thefluid heated moves in the direction indicated by the arrow through atube T which includes convolutions within and absorbing heat from thestill furnace. As shown, the fuel supply is regulated by adjusting avalve J in the furnace fuel supply pipe J". The valve J is of the fluidpressure motor type, and is given opening and closing adjustments byincreasing and decreasing the control pressure transmitted to thepressure chamber of the valve J by a pipe'J The pressure in the pipe Jis varied by the adjustment of a so-called flapper valve J toward andaway from the bleed orifice nozzle J of an air controller unit deviceJA, continuously receiving air through a restricted orifice J in acompressed air supp y p pe J The air controller unit or device JA may beof any one of various known types, and as shown is of the typeillustrated in Patent Nos. 2,124,946 and 2,125,109, each granted July26, 1938, on a joint application of F. W. Side and myself.

tion of the control device JA is unnecessary,

since in respect to that device, the present invention is only with themeans through which its flapper valve J is adjusted in response tovariations in the temperatures to which two temperature responsiveelements es and et are respectively exposed. a

As shown, each of those elements is the bulb of an expansive fluidthermometer. The bulb es is subjected to the temperature in a selectedportion of the furnace, and the fluid pressure de-" pendent on thattemperature is transmitted by a capillary tube or pipe e from the bulbes to the stationary end of a Bourdon tube EA. The latter has itsmovable end connected, and giving angular movement, to an axial shaft-Ewhich carries an arm E The bulb et is shown as subjected to thetemperature at which the oil heated passes away from the furnace, andthe corresponding fluid pressure is transmitted from that bulb throughthe corresponding capillary tube or pipe connection e, to the stationaryend of a Bourdon tube EB which has its movable end connected to acorresponding axial shaft E' carrying an arm E The two Bourdon tubes EAand EB may be, and as shown are, identical in construction. Furthermore,angular'adjustments Further reference to the construction and operaofeach arm E effect angular adjustments of the control valve J of the aircontroller unit JA, but the'two arms iii eflect adjustments of the saidvalve J through different operating instrumentalities.

The oscillating arm E of the device EAis connected by a link E to adepending arm of a bell crank lever GA forming a part of the unit JA,and turning about the stationary axis of a fulcrum pivot GG. A secondand horizontally disposed arm of the lever GA, is connected by asuspension link G to one end of a floating lever FA. The other end ofthe floating lever FA is connected by a suspension link G tothehorizontally disposed arm of a second bell crank lever GB, also mountedto turn about the axis of the fulcrum pivot GG, and having its angularposition adjusted as hereinafter described, by means including a link1). As shown, the arms of the levers GA and GB to which the links G andG are connected, extend in generally opposed horizontal directions awayfrom the axis of the fulcrumpivot GG, when said levers are within their.normal range of adjustment.

Movements of the lever FA efiect adjustments of the valve J of thedevice, A, through a lever K which is pivoted to' turn about arelatively stationary pivot included in the unit JA. Said lever K hasone arm connected to the lever FA, between the ends of the latter, by apivot pin FK, and has a second arm carrying a pin K; The valve J of theunit JA is biased for movement into engagement with the nozzle J of thedevice JA, to thereby prevent air flow outwardly from the unit throughthe bleeder orifice, in said nozzle. As movements of the lever FA giverising and falling movements to the pivot pin 1 "K, the pin K of thelever K moves the valve J away from, and permits it to move back towardthenozzle J 4 Q I The movements of the valve J toward and away from thenozzle J increase and diminish the controlling air pressure within thedevice JA, and hence, in the pressure chamber of the motor pressurevalve J which is thereby actuated t variably throttle the flow through apipe J in accordance with the movements of the pivot pin The link Dwhich has one end connected to the uprising vertically disposed arm ofthe lever GB of the device JA, has its other end connected to a lever,or equalizing b'ar, QA at a point intermediate the ends of the latter.The lever QA is pivotally connected at its upper end to the free end ofan arm DA carried by a normally stationary rock shaft D" which may beangularly adjusted manually, as by means of a screw driver insertedin akerf in the end of said shaft. The latter is adapted to be held by afriction washer, or otherwise, in any position into which it isadjusted. The manually eflfected angular adjustments of the arm DA,giving angular adjustments to the lever GB-of the device JA. therebymodify the temperature which the control system tends to maintain in theportion of the fur- .nace in which the bulb es is located.

The lever QA and thereby the lever GB and \valve J, of the device JA,are each angularly adjusted to effect a corresponding variationefinterior of the element U is connected by a pipe J to the controlpressure chamber of an air controller device JB. The latter may be, andas shown is, identical in construction and form with the device JA. .Thedevice JB has its pressure chamber connected to the compressed airsupply piping J by a restricted orifice J. The lever GA of the device JBis connected by a link Eato the arm E? ofsthe Bourdon tubedevice EB. Thelever GB of the device JB is connected by a link D directly to the armDB of a manual adjusting device which'includes an adjustable shaft D andwhich is shown as exactly like the previously described manual adjustingdevice including the arm DA.

In the normal operation of the apparatus illustrated, the controller JAis actuated by the control element EA to increase and decrease the fuelsupply through the pipeJ", as required to maintain the furnacetemperature of the portion of the furnace in which the bulb es islocated at a particular value. That value is determined by, and varieswith, the adjustment of the lever GB of thecontroller JA. When thetemperature to which the'bulb es is responsive. rises above the propervalue, the resultant counter-c ockwise movement of the lever GB of thedevice JA increases the throttling eil'ect of the valve J on the bleederorifice of the controller 'JA, and thereby increases the pressuretransmitted through the pipe J to the valve J, which is thereby adjustedto diminish the flow of fuel to the furnace S through the pipe JConversely, when the last mentioned temperature falls below the valuefixed by the existing adjustment of the lever GB of the device JA, thevalve J is adjusted to increase the supply of fuel to the furnace S.

The lever GB of the controller JA is adjusted by the controller JB toincrease or decrease the furnace temperature which the controller JAtends to maintain, by a decrease or increase, respectively,- in the exitfluid temperature, to which the bulb et is responsive, above or belowthe predetermined value thereof. When that temperature rises above itspredetermined value, the arm E of the element EB turns counterclockwiseand, through the resultant increased throttling effect given to thevalve J of the controller JB, the pressure transmitted from the latterthrough the pipe J- to the bellows element U is increased. The resultantexpansion of the latter gives a clockwise adjustment to the lever GB ofthe controller JA. The last mentioned adjustment increases thethrottling effect of the valve J' of the controller JA, and therebydirectly causes a reduction in the fuel supply to the furnace throughthe pipe J In consequence of that adjustment, also, theelement EA willthereafter act to maintain a value of the temperature to which the bulbes responds, which is lower than that previously maintained.

When the temperature to which the bulb et is responsive fallsbelow itspredetermined value, the lever E of the element EB turns clockwise andcauses a lower pressure to be transmitted to the element U, therebyproducing a counterclockwise adjustment of the lever GB of thecontroller JA. That adjustment diminishes the control pressuremaintained by the element JA and thereby directly increases the fuel,supply to the furnace through the pipe J", and thereafter the elementEA operates to maintain the furnace temperature to which the bulb es isresponsive, at a higher value than was maintained prior tothatadjustment.

The ultimate result of the control apparatus illustrated, is to maintainthe exit fluid temperature to which the bulb et responds, approximatelyconstant and equal to predetermined value which is fixed by theadjustment of the manually adjustable device DA of the control unit JB.Owing to the heat inertia or furnace lag of the furnace S, theregulation provided for in-the apparatus illustrated,-will ordinarily bemore satisfactory, and less apt to involve objectionable hunting, thanif the apparatus shown were simplified by the elimination of one of theenerically claim certain generic features of inven- I tion disclosedherein.

While in accordance with the provisions of the statutes, I haveillustrated and described the best form of embodiment of my'mvention nowknown to me, it will be apparent to those skilled in the art thatchanges may be made in the forms of the apparatus disclosed withoutdeparting from the spirit of my invention as set forth in the appendedclaims, and that, in some cases, certain features of my invention may beused to advantage without a corresponding use of other features. i

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. The combination with a work heating furnace, of two air actuatedcontrollers each in-\ cluding adjustable valve means and operating meanstherefor comprising a horizontally disposed floating lever, suspensionmeans for said lever comprising two elements, one of said elements beinga rock lever connected to one end 'of said floating lever and mounted.for oscillatory adjustment about a horizontal axis to thereby raise andlower-said one end of the floating lever and the other element being avertically disposed ling pivotally connected at its lower end to thesecond end of said floating lever and adapted for longitudinaladjustment to thereby raise and lower said second end of the floatinglever, means for adjusting one of the said elements of one controller inaccordance with variations in temend of the floating lever and the otherelement being a vertically disposed link pivotally connected at itslower end to the second end of said floating lever and adapted forlongitudinal adjustment to thereby raise and lower said second end ofthe floating lever, means for adjusting one of the said elements of onecontroller in accordance with variations in a temperature condition ofthe heater, means through which the second element of the last mentionedcontroller is adjusted by the other controller, means for adjusting oneof the elements of said other com troller in accordance with variationsin the temperature of the fluid heated in said heater, and

means through which the first mentioned con-' troller regulates thesupply of heat to said heater.

3.. Control mechanism comprising in combination, two airactuatedcontrollers each includperature condition of the furnace, means 2. Thecombination with a fluidheater, of two air actuated controllers eachincluding adjustable valve means and operating mean-s thereforcomprising a horizontally disposed floating lever,

suspension means for said lever comprising twoelements, one of saidelements being a rock lever connected to one end of said floating leverand mounted for oscillatory adjustment about a horizontal axis tothereby raise and lower said one ing adjustable valve means andoperating means therefor comprising a horizontally disposed floatinglever, suspension means for said lever comprising two elements, one ofsaid elements being a rock lever connected to one end of said floatinglever and mounted for oscillatory adjustment about a horizontal axis tothereby raise and lower saidone end of the floating. lever and the otherelement being a vertically disposed link pivotally connected at itslower end to the second end of said floating lever and adapted forlongitudinal adjustment to thereby raise and lower said second end ofthe floating lever, means for adjusting one of the said elements of onecontroller in accordance with the departure of a control quantity from anormal value thereof, means through which the second element of the lastmentioned controller is adjusted by the other controller, means foradjusting one of the elements of said other controller in accordancewith the departure from the normal value \of a control quantity varyingindependently of the first mentioned control quantity, means foradjusting the second of thetwo elements of the last men.- tionedcontroller to vary the normal value of the last mentioned controlquantity, and a fluid pressure regulator actuated by the first mentionedcontroller and regulating the first mentioned control quantity.

" THOMAS R. HARRISON.

